I Found My Girlfriend In Bed With Six Guys, When I Arrived Home. I NEED ADVICE!!! Should I Get Back With Her?

My girlfriend and I have been together for quite sometime. We love the same movie, music, book, TV show, and etc. I really love my girlfriend, and I believe nobody can replace her. I love the way she smiles, her elegant eyes, and the way she giggles at my jokes. We currently attend a highschool, our last year, since we're seniors. Her and I have jobs to pay rent, so we can still live in our apartment. She works at wendy's, while I work at Lows. It kind help us live on our own, and it's really not that bad

I started noticing my girlfriend's strange behavior, at school. She stopped hanging out with me, and hung out with these group of guys, that I didn't know. One day, I confronted her about those group of guys, who she hung out with. She told me they were her close friends. She laughed in my face, and said that I'm just being jealous, since we've been arguing that week. Two weeks have gone by, and I got notified by my friend, that she kissed each of the guys in the lips, at school. Him and I only get to see each other at work. I didn't believe him, until he showed me the video of her ACTUALLY KISSING THEM!!! I said take over for me, I'm going home to sort this out. He said if I leave, they're going to fire me, since I always arrive late. I didn't say anything and left. I got home, and I heard noises coming from room. I ran in there and I see 6 guys banging my girlfriend. They all got they're clothes, to watch me and my girlfriend argue. She said she doesn't want to be committed and tried to tell me that a open relationship could benefit both partners. Long story short, I said I'm not having that, we argued more, and she left.

The next day my manager calls me to tell me I'm fired. I got evicted from my apartment, now I'm living with my parents again. I can't seem to get her out of my head. I usually see her 3 times at school, when I was dating her. Now I see her more, like 7-9 times. Should I get back with her, if it means to have an open relationship?